Title: The Hockey Puck

Broad Question: Does the temperature of the puck effect the variables of a puck?

Specific Question: Does the time the puck stays in the freezer effect the rate the temperature of the puck increases when used during a game and does the temperature of the puck and time in the freezer effect the height the puck bounces?

Hypothesis: I hypothesize that the puck that is frozen for the longest will stay frozen the longest and the puck that has the highest temperature will bounce the most.

Graph of Hypothesis

Variables

Independent Variable:

#1 The number of days the puck is in the freezer.

#2 The temperature of the puck.

Dependent Variable:

#1 The change in temperature over 20 minutes.

#2 The height the puck bounces.

Variables That Need To Be Controlled:

#1 a The amount of movement each puck gets during the twenty minutes.

#1 b The temperature of the air is the same.

#2 a The height the puck falls from.

#2 b The temperature of the air is the same.

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General Plan

I will bounce three pucks that have all been frozen for a different numbers of days to see if there is a relationship between how long a puck is frozen and how much it bounces. I will also bounce eight more pucks at different temperatures to see the relationship between temperature and the height of the bounce. I will use these bounces to come up with a linear equation and then bounce five more pucks to see if the equation is correct. Also, I will measure how the temperature changes of pucks frozen for different numbers of days changes over 20 minutes.

Potential Problems and Solutions

- I need 20 pucks and a temperature probe. I search multiple places for pucks and make sure I get a temperature probe the day I do my experiment.
- The ice could be covered in Snow. I will shovel off the rink and cover it with a tent/ easy up.
-It will be hard to measure the height of the puck with the naked eye. I will video the drops.

Safety and Environmental concerns

The ice can't be melting. The rink has to be clear. The rink has to be partly smooth. The air has to below 100 degrees Celsius.

Experimental Design

What is your experimental unit?

Does the temperature of the puck effect how high the puck bounces and how the temperature of the puck changes over 20 minutes.

Number Of Trials

I repeated taking the temperature of the puck 20 times for ten different pucks. I took the bounce measurements of fifteen different pucks.

Number of Observations

I took 215 observations.

When data will be collected

The data will be collected February 24th.

Where will data be collected?

At my house on my ice rink.

Resources and Budget Table

Item	Number needed	Where I will get this	Cost
Hockey Pucks	20	at my house	0$
A table	1	at my house	0$
Scale	1	at my house	0$
A camera	1	at my house	0$
A temperature Probe	1	at school	0$

Detailed Procedure

I will put 2 pucks in the freezer each day at 7:00 A.M starting on Friday February 15th. I will repeat this procedure for 10 days. I will do the experiment on Sunday February 24th. I will drop one puck from 4 1/2 feet three times. I will repeat that procedure for three pucks that have been in the freezer. These pucks will have been frozen for 1, 5 and 10 days. I will take a puck frozen for 2,3,4,6,7,8 and 9 days and warm these pucks to different temperatures. I will also drop these pucks. I will record this data and graph the average height each of the 10 pucks bounces. After I graph these, I will use the graph to calculate a linear equation. I will use this to estimate the bounce of five more pucks at certain temperatures to see if it is accurate. I will record this on a graph. I will take the other ten pucks that have been frozen for 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 days and move them around on the ice for 20 minutes. I will take the temperature of each puck after every minute. After 20 minutes I will stop the experiment. I will record the data on a graph. This experiment will take place on my ice rink outside my house.

Diagram

Photo List

Time Line

Begin experiment 2/6/13
Take pictures every day until the first week of march
Experiment done 3/1/13
Analysis done 3/7/13
Discussion/background 3/15/13
Wiki complete 3/15/13
Posters complete 3/22/13

Data Table

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Data Analysis

All Raw Data

Frozen 1 Day	Frozen 2 Days	Frozen 3 Days	Frozen 4 Days	Frozen 5 Days	Frozen 6 Days	Frozen 7 Days	Frozen 8 Days	Frozen 9 Days	Frozen 10 Days
-23	-22	-24	-21	-23	-22	-23	-23	-23	-23
-22	-23	-23	-21	-22	-21	-22	-22	-21	-22
-18	-20	-19	-19	-19	-19	-20	-19	-20	-19
-16	-14	-14	-16	-18	-18	-17	-19	-18	-18
-13	-12	-13	-16	-17	-17	-17	-15	-16	-18
-10	-9	-9	-12	-13	-14	-12	-12	-12	-13
-8	-5	-8	-9	-11	-13	-12	-11	-12	-11
-7	-6	-8	-9	-9	-11	-10	-9	-10	-10
-9	-8	-10	-8	-9	-10	-9	-9	-8	-9
-8	-7	-8	-7	-8	-9	-8	-7	-7	-9
-7	-6	-7	-6	-6	-7	-7	-7	-6	-8
-8	-7	-8	-5	-8	-6	-6	-5	-6	-8
-6	-5	-6	-6	-6	-6	-5	-5	-6	-6
-7	-7	-8	-5	-5	-6	-6	-6	-6	-6
-2	-1	-2	-6	-6	-6	-6	-6	-6	-6
-5	-5	-5	-6	-7	-7	-7	-6	-6	-6
-8	-8	-8	-6	-6	-7	-7	-6	-6	-7
-4	-5	-5	-6	-6	-7	-7	-6	-6	-7
-5	-5	-5	-6	-6	-7	-7	-6	-6	-7
-4	-4	-4	-5	-5	-6	-6	-6	-6	-6

Temp of Puck (Celcius)	Average Bounce Height (inches)
-14 (Frozen 10 Days)	4.5
-14 (Frozen 5 Days)	3.83
-14 (Frozen 1 Day)	6.83
-8	5.67
0	7.16
4	9.5
18	13
28	18.83
34	16.33
43	20.72
54	24.33

Temp of Puck (Celcius)	Prediction of Bounce Height (inches) Equation: y = 0.2822x + 8.5809	Actual Height of Bounce (inches)
6	10.27	9.5
11	11.69	10.67
30	16.78	15.67
37	18.72	17.83
40	19.55	20.17

Graphs

Photos

The Puck That Bounced the Least (14 degrees)

The Pucks In the Freezer

The Puck That Bounced the Most (54 Degrees)

Results

The puck that was in for more time was 2 degrees Celsius colder at the end of the 20 minutes. The puck that was frozen for ten days actually bounced a little higher than one that was only frozen for 5 days. The puck that was frozen for only one day bounced higher then the ones frozen for 10 and 5 days. As the temperature of the puck increased, the height the puck bounced increased. The lowest bounce was the puck that was frozen for 5 days and had a temperature of -14 degrees Celsius (3.83 inches). The puck that was heated to 54 degrees Celsius bounced the highest (24.33 inches). This means that the NHL should change the puck every period because as the puck gets warmer, it bounces more. Also, that it doesn't make that much of a difference that they freeze it for 10 days but it is a little better if they freeze it.

Conclusion

The number of days frozen doesn't make a big difference in the rate of change in the temperature of the puck over twenty minutes so this part of my hypothesis was incorrect. My hypothesis that the highest temperature puck would bounce the most was correct. The puck bounced higher when the temperature was higher because the warmer the puck, the more energy in the puck. I concluded that there was a relationship between the temperature of the puck and how high it bounced. The linear equation that I came up with based on my data was y = 0.2822x + 8.5809. The x represents the temperature and the y represents the bounce height. So the NHL should freeze the puck because that does effect the bounce.

This benefits hockey in the NHL because they shoot really fast and if the puck was bouncing everywhere it could be dangerous. The pucks aren't even frozen for games in the league that I play in. The pucks are just out of the coaches bucket of pucks. We don't shoot it hard enough for it to bounce around too much so in the league I am in it doesn't matter. I concluded that the puck being frozen for ten days did not effect the rate of the temperature rising in a NHL regulation period which is 20 minutes. I also concluded that the higher the temperature of the puck, the more it bounced when dropped from a constant height.

Discussion

The NHL freezes the puck for ten days before every game and changes the puck after every 20 minute period. I decided to investigate why they do this. I concluded that the puck being frozen for ten days did not affect the rate of the temperature rising in an NHL regulation period which is 20 minutes. However, all of the pucks tested stayed frozen (below 0⁰C) for the entire 20 minutes they were played with on the ice. I also concluded that the higher the temperature of the puck, the more it bounced when dropped from a constant height. The patterns show that the temperature affects the bounce. When the temperature is lower the puck bounces less, when the temperature is higher the puck bounces higher. This part of the experiment was successful. It provided a good answer to my experimental question. There were no problems with my experiment. It went smoothly. I could have improved this by seeing if the temperature of the ice affects the bounce height.



Benefit to Community and/or Science

This experiment proved that the puck should be frozen. Keeping the puck in the freezer for at least a day kept the temperature below freezing. Using a frozen puck is a lot safer for everyone on the ice. I proved that pucks that are frozen will bounce less. With guys like Zdeno Chara taking a slap shot at 108 miles an hour it's good that the puck doesn't bounce as much. The puck would not be controllable because the puck would be bouncing all over the glass and boards. If you hit the post it would be at head level so it could hit someone without them having time to react. The puck doesn't bounce as much because it is compact. That is good for the game so it is safer.

Background Research

The hockey puck doesn't bounce as high when it is frozen because the hockey puck is made of rubber and sulfur. The sulfur keeps the puck from bouncing a lot. There is still rubber in the puck though. Rubber is one of the most elastic substances in the world. When rubber is heated it expands and gains energy. So when it bounces it has more of a bounce because the rubber has expanded. The expansion gives more of an acceptance to the hit on the ice. The rubber gets packed together and then released. The push of the rubber expanding out forces the puck to go higher. A frozen puck takes the energy out of the puck. The puck is compacted so it doesn't bounce. The puck is not expanded so when it hits the ice it is all ready compacted. That means it doesn't have any power when the rubber releases from the hit on the ice. The frozen puck absorbs the energy of the hit to the ice and doesn't transfer the energy to the expansion. The expansion only happens when the puck gets warmer.

References

http://www.jewelsfromthecrown.com/2009/06/01/why-hockey-pucks-are-frozen-kansas-city-star/

Abstract

The first thing I did on my project was I got 20 pucks. I put two in the freezer each day. Then on the tenth day I took the pucks and separated them. I took ten of them and used them for part one of my experiment. I slid them around on the ice for 20 minutes. Each minute I took the temperature of each one. While I did this I put the data in a table. Then I did part two. First, I dropped three of the other ten pucks. One puck was frozen for 1 day, one was frozen for 5, and the other was frozen for ten. After that I took the remaining seven pucks and heated those to different temperatures to see if the puck being really warm affected the bounce more. Then after that I graphed all the data from part 1 and 2. After that I used the data from part two to make a linear equation. The equation means that the bounce of the puck increases consistently as the pucks temperature increases. Using this equation, you can input the temperature of the puck and get the estimated bounce height. I used this data to estimate the bounce height of certain pucks. I did that to see if that equation was correct. After that I filled out my wiki page and all my other stuff. I wrote the conclusion, discussion, abstract, results, benefit to the community and science, and then I made my poster with all that on it. Then I presented this at the science fair!